三峡库区巫峡口-独龙高陡岸坡变形破坏机理研究

三峡库区自175 m 蓄水以来，地质灾害事件频发，尤其在地质环境脆弱的巫峡库岸段，2008年龚家方斜坡发生380000 m3崩滑，产生高达13 m 的涌浪，严重影响该库岸段航道运营安全。以巫峡口—独龙库岸段为研究区域，通过资料搜集、地面调查、工程地质测绘、山地工程等多种手段，在掌握其环境工程地质条件和岸坡岩体结构类型的基础上，根据库岸段内斜坡变形及破坏特征，划分出18个潜在不稳定斜坡。分析表明：该库岸段变形破坏模式为复合弯曲倾倒、“V”倾倒、剪切破坏，其可能诱发斜坡整体失稳模式为倾倒型和滑移型。总结出其存在累进性破坏、“锁固段”脆性破坏和整体性破坏3种机理。成果可为今后同类高陡岸坡的调查研究提供借鉴意义，同时为三峡库区防灾减灾、地质灾害工程治理提供依据。

Deformation and Failure Mechanism of High Steep Slope in the Area from Wu Gorge Entrance to Dulong of Three Gorges Reservoir Area

Geological disasters occurred frequently since the impoundment level of Three Gorges reservoir area reached 1 75mm.Especially in Wu Gorge where the geological environment is vulnerable,an amount of 380 000m3 collapsed at Gongjiafang slope in 2008,causing surge waves of 1 3m high,severely affecting the safety of waterway transportation.Through data gathering,ground investigation,engineering geology surveying and mapping,we re-searched the engineering geology and bank slope structure,and identified 1 8 potentially unstable slopes according to the bank slope’s deformation and failure features.Analysis shows that the deformation failure mode are compos-ite bending-toppling,V-shape toppling and interlayer shear failure,which would give rise to toppling and sliding instability.There are three failure mechanisms:progressive failure,brittle failure in “locked area”and integral failure.The research achievements provide reference for similar high steep bank slope research in the future and for disaster prevention and mitigation in Three Gorges area.